I have an Emachines £520 laptop with Windows Vista, which is about 6 months old. I have been doing regular backups via the link on my laptop, to a 500 gb external hard drive which was new at the same time. The external hard drive is now full up, I originally manually copied all my files across from the laptop, and also from my pc, before I sussed out how to do the back up, but other than that, I have only been using it to back up about once a month. Each back up listed shows as "0" bytes under properties, so I don't know what I'm supposed to remove to create more space, without losing essential data. I hope this makes sense!
Have you ever considered deleting all the previous back-ups from your external hard drive then doing your usual backup from your lap top. Alternatively, you could buy a spare external hard drive, do a back-up, then when you know that was successful re-format the original external hard drive to start again from empty.
I have considered deleting the previous backups, but as they showed as having 0 bytes in the properties, i wasn'tsure it would do any good. Should I delete them all or just the earlier ones?